A 220-Meter-Deep Hole from an Old Iron Mine Is Now a Turquoise Lake with Plans to Store the Largest Clean Energy in the Country

What was once a vast, echoing void carved deep into the earth by decades of iron mining has taken on a startling new identity. A 220-meter-deep pit, abandoned after the ore ran dry, is now filled with striking turquoise water—and is poised to become one of the largest clean-energy storage projects in the country. The transformation reflects a growing global trend: turning the relics of fossil-era industry into pillars of a low-carbon future.

The lake, formed naturally as groundwater and rainwater flooded the disused mine, has already become a visual symbol of renewal. But beneath its calm surface lies an ambitious plan that could reshape how renewable energy is stored and delivered at scale.

From Extraction to Energy Storage

For decades, the iron mine was a driver of local employment and industrial output, but it also left behind environmental damage and an immense open pit once operations ceased. Like many abandoned mines around the world, it posed long-term challenges: unstable geology, water contamination risks, and limited prospects for redevelopment.

Engineers and energy planners, however, saw opportunity where others saw liability. The mine’s extreme depth, stable rock walls, and existing infrastructure made it an ideal candidate for pumped-storage hydropower, a technology often described as the world’s most mature and reliable form of large-scale energy storage.

In pumped storage systems, electricity is used to pump water from a lower reservoir to a higher one when energy supply exceeds demand—typically during periods of strong wind or intense sunshine. When demand rises, the water is released back down through turbines, generating electricity. In this case, the mine pit itself would serve as the lower reservoir, while a newly constructed upper reservoir would sit hundreds of meters above.

Why a Turquoise Lake Matters

The lake’s vivid turquoise color, caused by mineral composition and light refraction, has drawn public attention, but its importance goes far beyond aesthetics. Its depth of 220 meters provides a substantial “head,” or vertical drop, which is critical for efficient hydropower generation. The greater the height difference between reservoirs, the more energy can be stored and released.

According to project planners, once fully operational the facility could store more clean energy than any other project of its kind in the country, capable of delivering electricity for hours or even days during periods of peak demand or grid stress. That makes it particularly valuable as nations expand renewable energy capacity and grapple with intermittency—the fact that the sun does not always shine and the wind does not always blow.

A Backbone for Renewable Expansion

As solar and wind power grow, energy storage has become one of the central challenges of the energy transition. Batteries work well for short durations, but they can be expensive, resource-intensive, and less practical for multi-day storage at national scale.

Pumped-storage hydropower fills that gap. It can operate for decades, store vast amounts of energy, and respond quickly to changes in grid demand. By repurposing an existing mine, developers can avoid many of the environmental and social hurdles associated with building new dams and reservoirs from scratch.

In effect, the old iron mine could become a giant green battery, stabilizing the national grid and reducing reliance on fossil-fuel-powered backup plants.

Environmental and Community Benefits

The project also promises environmental gains beyond clean electricity. Stabilizing and managing the flooded mine reduces the risk of uncontrolled water discharge, which can contaminate surrounding ecosystems. Careful monitoring and treatment systems are being designed to ensure water quality is maintained throughout operation.

For nearby communities, the transformation offers a new economic narrative. Regions that once depended on mining jobs often struggle after closure, facing unemployment and population decline. The clean-energy project brings construction work, long-term technical roles, and the chance to reposition the area as a hub of sustainable innovation.

Some proposals also include controlled public access, educational centers, or viewpoints overlooking the lake—turning a former industrial wound into a landmark of regeneration.

Technical and Safety Challenges

Despite its promise, the project is not without complexity. Engineers must ensure the mine’s rock walls remain stable under fluctuating water levels and pressure changes. Extensive geological surveys, reinforcement measures, and real-time monitoring systems are central to the design.

There are also regulatory and financial hurdles. Large infrastructure projects require long approval processes, significant upfront investment, and coordination between energy authorities, environmental agencies, and local governments. Supporters argue, however, that the long lifespan and strategic importance of the facility justify the costs.

A Model for the Future?

Around the world, thousands of deep open-pit mines sit abandoned, relics of an extractive past. If even a fraction of them can be safely converted into energy storage sites, they could collectively play a major role in decarbonizing power systems.

The turquoise lake in this former iron mine stands as a powerful metaphor: the same ground that once fueled industrial growth through extraction may now underpin a cleaner, more resilient energy system. By turning depth into strength and history into opportunity, the project suggests that the energy transition does not always require starting from scratch—sometimes, it begins by reimagining what we have already left behind.